Scanning apparatuses are widely used for scanning images of documents. The scanned images can be converted into electronic files, which are then stored, processed or spread. With increasing development of scanning technologies, the scanning apparatuses have experienced great growth and are now rapidly gaining in popularity.
FIG. 1 is a schematic perspective view illustrating a conventional scanning apparatus. As shown in FIG. 1, the conventional scanning apparatus 1 comprises a lower casing 10 and an upper cover 11. The lower casing 10 comprises a glass platform 101 and a scanning module 102. A document P to be scanned is placed on the glass platform 101. After the document P is placed on the glass platform 101, the lower casing 10 is covered by the upper cover 11, so that the document P is positioned in the scanning apparatus 1. During the scanning operation is done, the scanning module 102 is moved within the lower casing 10 to scan the document P.
FIG. 2 is a schematic cross-sectional view illustrating the conventional scanning apparatus. Hereinafter, the internal structure of the lower casing 10 of the conventional scanning apparatus 1 will be illustrated with reference to FIG. 2.
As shown in FIG. 2, in addition to the glass platform 101 and the scanning module 102, the lower casing 10 further comprises a transmission shaft 103 and a driving motor 104. The scanning module 102 is installed on the transmission shaft 103. The driving motor 104 is connected with the scanning module 102 for providing motive power to the scanning module 102, so that the scanning module 102 is moved along the transmission shaft 103. The scanning module 102 comprises a light source 1021, a fixed reflective mirror 1022, a lens 1023 and an optical sensing element 1024. The light source 1021 is a lamp tube. The incident light beams L emitted by the light source 1021 are projected on the document P. The incident light beams L reflected by the document P are then reflected by the fixed reflective mirror 1022, and focused by the lens 1023. The focused incident light beams L are received by the optical sensing element 1024, and then converted into corresponding image signals of the document P.
Hereinafter, a process for performing a scanning operation by the scanning apparatus 1 will be illustrated with reference to FIGS. 1 and 2. For scanning the document P by the scanning apparatus 1, the document P is firstly placed on the glass platform 101 of the lower casing 10. Then, the upper cover 11 is rotated toward the lower casing 10 to cover the lower casing 10 and fix the document P. After the document P is positioned in the scanning apparatus 1, the scanning apparatus 1 is activated, and a scanning operation for scanning the document P starts. The incident light beams L emitted by the light source 1021 are projected on the document P. The incident light beams L reflected by the document P are then reflected by the fixed reflective mirror 1022, and focused by the lens 1023. The focused incident light beams L are received by the optical sensing element 1024, and thus a first portion of the image of the document P is acquired. Moreover, when the scanning apparatus 1 is activated, the driving motor 104 is enabled to drive movement of the scanning module 102 along the transmission shaft 103. That is, the overall document P is scanned while moving the scanning module 102 along the transmission shaft 103. After the scanning operation is finished, the complete image of the document P is acquired.
However, the conventional scanning apparatus 1 still has some drawbacks. For example, if the incident light beams L emitted by the light source 1021 are not uniformly projected on the document P, the scanning quality of the scanning module 102 is deteriorated.
Therefore, there is a need of providing an improved scanning apparatus with enhanced scanning quality.